PROJECT SUMMARY/ABSTRACT A cornerstone of treatment uniformly recommended for individuals with bipolar disorder (BD) is mood stabilizing medication. However, approximately one in two individuals with BD are non -adherent with medication, often leading to severe and negative consequences. Unfortunately, there is no widely used evidence-based approach to target poor adherence in BD. Customized Adherence Enhancement (CAE), developed by this study team, is a brief, practical BD -specific approach that identifies individual adherence barriers and then targets these areas for intervention using a flexibly-administered modular format. A prospective, 6-month, randomized controlled efficacy trial (RCT) of CAE vs. a rigorous control, BD-specific education (EDU) found that medication adherence and functional status were improved in CAE vs. EDU for poorly-adherent patients. Remarkably, the benefits of CAE occurred in individuals who had been living with BD, on average, for over 2 decades. While promising, the original efficacy RCT was limited by the fact that it was performed in an academic medical center, did not make use of existing web/text messaging technology, and did not address potential challenges to scale -up in standard clinical settings. In response to PA-18-722 ?Improving Patient Adherence to Treatment and Prevention Regimens to Promote Health?, this Type 1 hybrid effectiveness-implementation project will adapt CAE for use in community/public- sector care settings, test effectiveness in high-risk, poorly adherent individuals in these settings, and gather evidence on barriers and facilitators to implementation of the intervention in order to inform subsequent scale- up. The project will examine putative mechanistic engagement targets suggested by previous work and include implementation elements that will inform future dissemination should findings be positive. The project will be implemented in 4 specific aims: 1) Refine the CAE intervention guided by stakeholders at a community mental health clinic (CMHC) and a safety-net county healthcare system, 2) Test the effectiveness of technology- facilitated CAE vs. enhanced treatment as usual (eTAU) using a prospective, 2-site RCT, 3) Test the effects of CAE vs. eTAU on functional status in poorly adherent individuals with BD, and 4) Identify barriers and facilitators to CAE implementation in order to inform subsequent scale-up and spread using qualitative methods and guided by implementation conceptual models. Additional exploratory analysis will assess whether changes in patient- level adherence barriers and facilitators mediate the treatment effects on adherence. Finally, the project will evaluate on-site (outpatient visits, no-show rates) and off-site (emergency department visits, hospitalizations) health resource use to help characterize relative value and inform future sustainability efforts. An over-arching goal of this project will be to provide a curriculum-driven adherence enhancement approach that can be implemented in public-sector care settings and which can improve outcomes for the most vulnerable groups of people with BD.